1. Field of the Invention
The invention relates to an active-matrix display device such as a liquid crystal display device, and electronic equipment using the same.
2. Description of the Related Art
In recent years, portable terminals such as a cellular phone and PDA (personal Digital Assistants) are rapidly becoming widespread. As one of factors for the rapid spread of these portable terminals, a liquid crystal display device mounted as an output display unit thereof can be cited. The reason is that the liquid crystal display device has a characteristic in which electric power is not necessary in principle to drive the liquid crystal display and that it is a low-power consumption display device.
FIG. 1 is a block diagram showing a configuration example of a general liquid crystal display device.
A liquid crystal display device 1 includes an available display area unit 2, a vertical drive circuit (VDRV) 3, and a horizontal drive circuit (HDRV) 4 as shown in FIG. 1.
In the available display area unit 2, plural pixel units 2PXLs are arranged in a matrix state.
Each pixel unit 2PXL includes a thin-film transistor (TFT) 21 as a switching element, a liquid crystal cell LC22 in which a pixel electrode 22 is connected to a drain electrode (or a source electrode) of the TFT 21 and a storage capacitor CS21 in which one of electrodes is connected to the drain electrode of the TFT 21.
With respect to respective pixel units 2PXLs, scanning lines 5-1 to 5-m and storage capacitor line (CS line) 6-1 to 6-m are arranged at each row along the pixel arrangement direction and signal lines 7-1 to 7-n are arranged at each column along the pixel arrangement direction.
Gate electrodes of the TFTs 21 of respective pixel units 2PXLs are connected to the scanning lines (gate line) 5-1 to 5-m respectively so that gate electrodes of each row correspond to the same scanning line. Source electrodes (or drain electrodes) of respective pixel units 2PXLs are connected to the signal lines 7-1 to 7-n respectively so that source electrodes (or drain electrodes) of each column correspond to the same signal line.
Furthermore, in the general liquid crystal display device, ones of electrodes (electrodes opposite to the connected electrodes) of the storage capacitors CS21 of respective pixel units 2PXL are connected to the storage capacitor lines 6-1 to 6-m respectively so that electrodes at each row correspond to the same storage capacitor line.
The respective scanning lines 5-1 to 5-m and respective storage capacitor lines 6-1 to 6-m are driven by the vertical drive circuit 3 and the respective signal lines 7-1 to 7-n are driven by the horizontal drive circuit 4.
In the vertical drive circuit 3, scanners (shift registers) 31, CS latches 32 and gate buffers 33 are connected in series and arranged at respective rows of the pixel arrangement so as to correspond to respective scanning lines 5-1 to 5-m and respective storage capacitor lines 6-1 to 6-m.
The liquid crystal display device 1 having the above configuration applies a drive method of giving additional potential to the pixel electrodes 22 of the pixel units 2PXLs by using coupling.
In the vertical drive circuit 3, a certain pulse is scanned in the scanner (shift register) 31 to generate a GV and CV pulses.
Then, polarity of the FRP pulse is detected by using the GV and GS pulses in the CS latch to generate a CSout pulse to be coupled to the pixel electrode 22.
At this time, a signal Vout for turning on the TFT 21 of the pixel unit 2PXL is generated simultaneously.
Lastly, pulse shaping is performed at the gate buffer 33 and pulses are outputted to the gate lines 5-1 to 5-m and the CS lines 6-1 to 6-m respectively.